Lingual flap retraction and prevention of lingual nerve damage associated with third molar surgery: a systematic review of the literature.

OBJECTIVE: Lingual nerve damage sometimes occurs after the removal of third molars. The use of a lingual retractor has been advocated to protect the lingual nerve. A systematic review of the literature was undertaken to evaluate the incidence of lingual nerve damage after third molar surgery and the effect of a lingual retractor on nerve damage. STUDY
DESIGN: An exhaustive computerized search of several databases and references cited in the various studies was performed. Predetermined inclusion and exclusion criteria were used to identify the 8 published studies acceptable for detailed analysis. The incidence and spontaneous recovery of lingual nerve injury for the following 3 surgical techniques were evaluated: the buccal approach with lingual flap retraction (BA+), or the buccal approach without lingual flap retraction (BA-), and the lingual split technique with lingual flap retraction (LS).
RESULTS: In the 8 selected articles, lingual nerve injury occurred in 9.6%, 6.4%, and 0.6% of the pooled LS, BA+, and BA- procedures, respectively. On the basis of risk ratios comparing combined incidence rates, lingual nerve injury is 8.8 times more likely to occur in BA+ than in BA- procedures (CI = 4.3-17.8), 13.3 times more likely to occur in LS than in BA- procedures (CI = 6.6-26.9), and 1.5 times more likely to occur in LS than in BA+ procedures (CI = 1.2-1.8). Permanent lingual nerve injury occurred in 0.1%, 0.6%, and 0.2% of the combined LS, BA+, and BA- procedures, respectively. The combined permanent incidence risk ratios were not calculated because of the low permanent incidence rates.
CONCLUSIONS: The use of a lingual nerve retractor during third molar surgery was associated with an increased incidence of temporary nerve damage and was neither protective nor detrimental with respect to the incidence of permanent nerve damage.